This invention is broadly applicable to the art of dispensing, especially to dispensing flowable products or fluids of all types, specifically to dispensing multicomponent products such as two-component foam plastics. Dispensing the product with a somewhat constant rate of flow requires that the pressure within the bulk container be supplemented as the product volume decreases due to use. In some containers, this need is met by providing a means for supplying additional gas, such as air, carbon dioxide or nitrogen into the container as required. However, this requires an added pump or gas cylinder, which is expensive and wasteful and in some cases results in an uneven pressure profile.
The art contains at least one successful apparatus for pressurizing a bulk container for flowable product without requiring expensive and wasteful supplemental equipment. This art is found in U.S. Pat. No. 4,923,095 to Dorfman et al. According to the teachings of the Dorfman patent, a scaled, expandable pouch or bladder contains a two-component gas generating system, such as citric acid and bicarbonate of soda. Initially, the two components are physically isolated so that they do not generate gas. The pouch can be inserted into a beverage container, such as a keg or large bottle, and the container then can be filled with beverage and sealed. At some point in time, either shortly before inserting the pouch or at a later time, the two components of the gas generating system must be placed in mutual contact so as to generate gas to expand the pouch and thereby pressurize the container to dispense the beverage. The pouch contains a plurality of sub-compartments so that it can expand in stages. As the beverage volume progressively decreases, pressure within the pouch progressively opens new sub-compartments. Each sub-compartment contains a component of the gas generating system, with the result that as each sub-compartment is opened, more gas can be generated.
The technology of the Dorfman patent effectively solves certain problems in the dispensing industry, especially in dispensing beverages. However, unsolved problems remain in the area of dispensing products that require relatively higher pressures or that require especially uniform application of pressure. Further, Dorfman does not provide a means for supplying a gas stream for atomizing and dispensing the product.
U.S. Ser. No. 07/968,834, filed Oct. 30, 1992, and titled "Pressure Activated Trigger" discloses an improvement of the Dorfman technology, wherein a pressure-rupturable membrane separates one component of the gas generating system from the second component. The components are mixed when an externally applied pressure charge ruptures the membrane.
U.S. Pat. No. 5,106,597 to Plester et al discloses a gas generator using a two-component, acid-base system, in which the components are brought together under self-controlled conditions causing gas generation and release at a predetermined pressure. However, this system operates at artificially elevated pressures, initiated by a starting charge that drives the generating reaction. In addition, a considerable amount of mechanical regulating equipment is required.
U.S. Pat. No. 5,021,219 to Rudick et al discloses another acid-base gas generating system, in which an acid chamber is at a higher pressure than the base/reaction chamber, and a pressure regulator valve separates to two and permits acid to feed when pressure in the base/reaction chamber is lower than a set limit. This system also requires artificially elevated pressures.
It would be desirable to develop a pressure generator that stores and ships at atmospheric pressure and without complex or expensive mechanical valves and pressure regulators.
Similarly, it would be desirable to have a simple and inexpensive chemical and mechanical system for amplifying small changes in pressure to regulate the pressure in a larger volume.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the pressure regulator and amplifier and method of operation of this invention may comprise the following.